By Robert Preidt
For women, however, weight did not affect survival, according to the study.
"The question is, what underlying mechanism causes this advantage in obese men, and can we take advantage of it to improve outcomes in patients with melanoma?" said the study's lead author, Dr. Jennifer McQuade. She's an instructor of melanoma medical oncology at the University of Texas MD Anderson Cancer Center.
"One hint may be the interaction between obesity, sex and outcomes, which has not been detected before in any cancer," McQuade said in a news release from the cancer center.
It's long been known that women with advanced melanoma live longer than men with the disease. The researchers said their finding that obesity overcomes this survival disadvantage for men will lead them to examine the role of sex hormones.
The study involved about 1,900 people whose advanced melanoma was treated with targeted therapy, immunotherapy or chemotherapy. Overall, obese men lived from about 27 to 37 months after treatment, depending on the treatment, compared with 14 to 20 months for men of normal weight. Women lived about 33 months after treatment, regardless of their weight, the study found.
Although the study found an association between weight and survival after melanoma treatment in men, it did not prove a cause-and-effect relationship.
"The public health message is not that obesity is good. Obesity is a proven risk factor for many diseases," McQuade stressed.
"Even within our metastatic melanoma population, we would not suggest that patients intentionally gain weight," she said. "We need to figure out what is driving this paradox and learn how to use this information to benefit all of our patients."
The findings were published online Feb. 12 in The Lancet Oncology.